net/sched/act_ipt.c

   1 /*
   2  * net/sched/act_ipt.c          iptables target interface
   3  *
   4  *TODO: Add other tables. For now we only support the ipv4 table targets
   5  *
   6  *              This program is free software; you can redistribute it and/or
   7  *              modify it under the terms of the GNU General Public License
   8  *              as published by the Free Software Foundation; either version
   9  *              2 of the License, or (at your option) any later version.
  10  *
  11  * Copyright:   Jamal Hadi Salim (2002-13)
  12  */
  13
  14 #include <linux/types.h>
  15 #include <linux/kernel.h>
  16 #include <linux/string.h>
  17 #include <linux/errno.h>
  18 #include <linux/skbuff.h>
  19 #include <linux/rtnetlink.h>
  20 #include <linux/module.h>
  21 #include <linux/init.h>
  22 #include <linux/slab.h>
  23 #include <net/netlink.h>
  24 #include <net/pkt_sched.h>
  25 #include <linux/tc_act/tc_ipt.h>
  26 #include <net/tc_act/tc_ipt.h>
  27
  28 #include <linux/netfilter_ipv4/ip_tables.h>
  29
  30
  31 #define IPT_TAB_MASK     15
  32
  33 static int ipt_net_id;
  34
  35 static int xt_net_id;
  36
  37 static int ipt_init_target(struct xt_entry_target *t, char *table, unsigned int hook)
  38 {
  39         struct xt_tgchk_param par;
  40         struct xt_target *target;
  41         int ret = 0;
  42
  43         target = xt_request_find_target(AF_INET, t->u.user.name,
  44                                         t->u.user.revision);
  45         if (IS_ERR(target))
  46                 return PTR_ERR(target);
  47
  48         t->u.kernel.target = target;
  49         par.table     = table;
  50         par.entryinfo = NULL;
  51         par.target    = target;
  52         par.targinfo  = t->data;
  53         par.hook_mask = hook;
  54         par.family    = NFPROTO_IPV4;
  55
  56         ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
  57         if (ret < 0) {
  58                 module_put(t->u.kernel.target->me);
  59                 return ret;
  60         }
  61         return 0;
  62 }
  63
  64 static void ipt_destroy_target(struct xt_entry_target *t)
  65 {
  66         struct xt_tgdtor_param par = {
  67                 .target   = t->u.kernel.target,
  68                 .targinfo = t->data,
  69                 .family   = NFPROTO_IPV4,
  70         };
  71         if (par.target->destroy != NULL)
  72                 par.target->destroy(&par);
  73         module_put(par.target->me);
  74 }
  75
  76 static void tcf_ipt_release(struct tc_action *a, int bind)
  77 {
  78         struct tcf_ipt *ipt = to_ipt(a);
  79         ipt_destroy_target(ipt->tcfi_t);
  80         kfree(ipt->tcfi_tname);
  81         kfree(ipt->tcfi_t);
  82 }
  83
  84 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
  85         [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ },
  86         [TCA_IPT_HOOK]  = { .type = NLA_U32 },
  87         [TCA_IPT_INDEX] = { .type = NLA_U32 },
  88         [TCA_IPT_TARG]  = { .len = sizeof(struct xt_entry_target) },
  89 };
  90
  91 static int __tcf_ipt_init(struct tc_action_net *tn, struct nlattr *nla,
  92                           struct nlattr *est, struct tc_action *a, int ovr,
  93                           int bind)
  94 {
  95         struct nlattr *tb[TCA_IPT_MAX + 1];
  96         struct tcf_ipt *ipt;
  97         struct xt_entry_target *td, *t;
  98         char *tname;
  99         int ret = 0, err, exists = 0;
 100         u32 hook = 0;
 101         u32 index = 0;
 102
 103         if (nla == NULL)
 104                 return -EINVAL;
 105
 106         err = nla_parse_nested(tb, TCA_IPT_MAX, nla, ipt_policy);
 107         if (err < 0)
 108                 return err;
 109
 110         if (tb[TCA_IPT_INDEX] != NULL)
 111                 index = nla_get_u32(tb[TCA_IPT_INDEX]);
 112
 113         exists = tcf_hash_check(tn, index, a, bind);
 114         if (exists && bind)
 115                 return 0;
 116
 117         if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) {
 118                 if (exists)
 119                         tcf_hash_release(a, bind);
 120                 return -EINVAL;
 121         }
 122
 123         td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]);
 124         if (nla_len(tb[TCA_IPT_TARG]) < td->u.target_size)
 125                 return -EINVAL;
 126
 127         if (!tcf_hash_check(tn, index, a, bind)) {
 128                 ret = tcf_hash_create(tn, index, est, a, sizeof(*ipt), bind,
 129                                       false);
 130                 if (ret)
 131                         return ret;
 132                 ret = ACT_P_CREATED;
 133         } else {
 134                 if (bind)/* dont override defaults */
 135                         return 0;
 136                 tcf_hash_release(a, bind);
 137
 138                 if (!ovr)
 139                         return -EEXIST;
 140         }
 141         ipt = to_ipt(a);
 142
 143         hook = nla_get_u32(tb[TCA_IPT_HOOK]);
 144
 145         err = -ENOMEM;
 146         tname = kmalloc(IFNAMSIZ, GFP_KERNEL);
 147         if (unlikely(!tname))
 148                 goto err1;
 149         if (tb[TCA_IPT_TABLE] == NULL ||
 150             nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ)
 151                 strcpy(tname, "mangle");
 152
 153         t = kmemdup(td, td->u.target_size, GFP_KERNEL);
 154         if (unlikely(!t))
 155                 goto err2;
 156
 157         err = ipt_init_target(t, tname, hook);
 158         if (err < 0)
 159                 goto err3;
 160
 161         spin_lock_bh(&ipt->tcf_lock);
 162         if (ret != ACT_P_CREATED) {
 163                 ipt_destroy_target(ipt->tcfi_t);
 164                 kfree(ipt->tcfi_tname);
 165                 kfree(ipt->tcfi_t);
 166         }
 167         ipt->tcfi_tname = tname;
 168         ipt->tcfi_t     = t;
 169         ipt->tcfi_hook  = hook;
 170         spin_unlock_bh(&ipt->tcf_lock);
 171         if (ret == ACT_P_CREATED)
 172                 tcf_hash_insert(tn, a);
 173         return ret;
 174
 175 err3:
 176         kfree(t);
 177 err2:
 178         kfree(tname);
 179 err1:
 180         if (ret == ACT_P_CREATED)
 181                 tcf_hash_cleanup(a, est);
 182         return err;
 183 }
 184
 185 static int tcf_ipt_init(struct net *net, struct nlattr *nla,
 186                         struct nlattr *est, struct tc_action *a, int ovr,
 187                         int bind)
 188 {
 189         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 190
 191         return __tcf_ipt_init(tn, nla, est, a, ovr, bind);
 192 }
 193
 194 static int tcf_xt_init(struct net *net, struct nlattr *nla,
 195                        struct nlattr *est, struct tc_action *a, int ovr,
 196                        int bind)
 197 {
 198         struct tc_action_net *tn = net_generic(net, xt_net_id);
 199
 200         return __tcf_ipt_init(tn, nla, est, a, ovr, bind);
 201 }
 202
 203 static int tcf_ipt(struct sk_buff *skb, const struct tc_action *a,
 204                    struct tcf_result *res)
 205 {
 206         int ret = 0, result = 0;
 207         struct tcf_ipt *ipt = a->priv;
 208         struct xt_action_param par;
 209
 210         if (skb_unclone(skb, GFP_ATOMIC))
 211                 return TC_ACT_UNSPEC;
 212
 213         spin_lock(&ipt->tcf_lock);
 214
 215         ipt->tcf_tm.lastuse = jiffies;
 216         bstats_update(&ipt->tcf_bstats, skb);
 217
 218         /* yes, we have to worry about both in and out dev
 219          * worry later - danger - this API seems to have changed
 220          * from earlier kernels
 221          */
 222         par.net      = dev_net(skb->dev);
 223         par.in       = skb->dev;
 224         par.out      = NULL;
 225         par.hooknum  = ipt->tcfi_hook;
 226         par.target   = ipt->tcfi_t->u.kernel.target;
 227         par.targinfo = ipt->tcfi_t->data;
 228         par.family   = NFPROTO_IPV4;
 229         ret = par.target->target(skb, &par);
 230
 231         switch (ret) {
 232         case NF_ACCEPT:
 233                 result = TC_ACT_OK;
 234                 break;
 235         case NF_DROP:
 236                 result = TC_ACT_SHOT;
 237                 ipt->tcf_qstats.drops++;
 238                 break;
 239         case XT_CONTINUE:
 240                 result = TC_ACT_PIPE;
 241                 break;
 242         default:
 243                 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n",
 244                                        ret);
 245                 result = TC_POLICE_OK;
 246                 break;
 247         }
 248         spin_unlock(&ipt->tcf_lock);
 249         return result;
 250
 251 }
 252
 253 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 254 {
 255         unsigned char *b = skb_tail_pointer(skb);
 256         struct tcf_ipt *ipt = a->priv;
 257         struct xt_entry_target *t;
 258         struct tcf_t tm;
 259         struct tc_cnt c;
 260
 261         /* for simple targets kernel size == user size
 262          * user name = target name
 263          * for foolproof you need to not assume this
 264          */
 265
 266         t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 267         if (unlikely(!t))
 268                 goto nla_put_failure;
 269
 270         c.bindcnt = ipt->tcf_bindcnt - bind;
 271         c.refcnt = ipt->tcf_refcnt - ref;
 272         strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name);
 273
 274         if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) ||
 275             nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) ||
 276             nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) ||
 277             nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) ||
 278             nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname))
 279                 goto nla_put_failure;
 280         tm.install = jiffies_to_clock_t(jiffies - ipt->tcf_tm.install);
 281         tm.lastuse = jiffies_to_clock_t(jiffies - ipt->tcf_tm.lastuse);
 282         tm.expires = jiffies_to_clock_t(ipt->tcf_tm.expires);
 283         if (nla_put(skb, TCA_IPT_TM, sizeof (tm), &tm))
 284                 goto nla_put_failure;
 285         kfree(t);
 286         return skb->len;
 287
 288 nla_put_failure:
 289         nlmsg_trim(skb, b);
 290         kfree(t);
 291         return -1;
 292 }
 293
 294 static int tcf_ipt_walker(struct net *net, struct sk_buff *skb,
 295                           struct netlink_callback *cb, int type,
 296                           struct tc_action *a)
 297 {
 298         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 299
 300         return tcf_generic_walker(tn, skb, cb, type, a);
 301 }
 302
 303 static int tcf_ipt_search(struct net *net, struct tc_action *a, u32 index)
 304 {
 305         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 306
 307         return tcf_hash_search(tn, a, index);
 308 }
 309
 310 static struct tc_action_ops act_ipt_ops = {
 311         .kind           =       "ipt",
 312         .type           =       TCA_ACT_IPT,
 313         .owner          =       THIS_MODULE,
 314         .act            =       tcf_ipt,
 315         .dump           =       tcf_ipt_dump,
 316         .cleanup        =       tcf_ipt_release,
 317         .init           =       tcf_ipt_init,
 318         .walk           =       tcf_ipt_walker,
 319         .lookup         =       tcf_ipt_search,
 320 };
 321
 322 static __net_init int ipt_init_net(struct net *net)
 323 {
 324         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 325
 326         return tc_action_net_init(tn, &act_ipt_ops, IPT_TAB_MASK);
 327 }
 328
 329 static void __net_exit ipt_exit_net(struct net *net)
 330 {
 331         struct tc_action_net *tn = net_generic(net, ipt_net_id);
 332
 333         tc_action_net_exit(tn);
 334 }
 335
 336 static struct pernet_operations ipt_net_ops = {
 337         .init = ipt_init_net,
 338         .exit = ipt_exit_net,
 339         .id   = &ipt_net_id,
 340         .size = sizeof(struct tc_action_net),
 341 };
 342
 343 static int tcf_xt_walker(struct net *net, struct sk_buff *skb,
 344                          struct netlink_callback *cb, int type,
 345                          struct tc_action *a)
 346 {
 347         struct tc_action_net *tn = net_generic(net, xt_net_id);
 348
 349         return tcf_generic_walker(tn, skb, cb, type, a);
 350 }
 351
 352 static int tcf_xt_search(struct net *net, struct tc_action *a, u32 index)
 353 {
 354         struct tc_action_net *tn = net_generic(net, xt_net_id);
 355
 356         return tcf_hash_search(tn, a, index);
 357 }
 358
 359 static struct tc_action_ops act_xt_ops = {
 360         .kind           =       "xt",
 361         .type           =       TCA_ACT_XT,
 362         .owner          =       THIS_MODULE,
 363         .act            =       tcf_ipt,
 364         .dump           =       tcf_ipt_dump,
 365         .cleanup        =       tcf_ipt_release,
 366         .init           =       tcf_xt_init,
 367         .walk           =       tcf_xt_walker,
 368         .lookup         =       tcf_xt_search,
 369 };
 370
 371 static __net_init int xt_init_net(struct net *net)
 372 {
 373         struct tc_action_net *tn = net_generic(net, xt_net_id);
 374
 375         return tc_action_net_init(tn, &act_xt_ops, IPT_TAB_MASK);
 376 }
 377
 378 static void __net_exit xt_exit_net(struct net *net)
 379 {
 380         struct tc_action_net *tn = net_generic(net, xt_net_id);
 381
 382         tc_action_net_exit(tn);
 383 }
 384
 385 static struct pernet_operations xt_net_ops = {
 386         .init = xt_init_net,
 387         .exit = xt_exit_net,
 388         .id   = &xt_net_id,
 389         .size = sizeof(struct tc_action_net),
 390 };
 391
 392 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)");
 393 MODULE_DESCRIPTION("Iptables target actions");
 394 MODULE_LICENSE("GPL");
 395 MODULE_ALIAS("act_xt");
 396
 397 static int __init ipt_init_module(void)
 398 {
 399         int ret1, ret2;
 400
 401         ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops);
 402         if (ret1 < 0)
 403                 pr_err("Failed to load xt action\n");
 404
 405         ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops);
 406         if (ret2 < 0)
 407                 pr_err("Failed to load ipt action\n");
 408
 409         if (ret1 < 0 && ret2 < 0) {
 410                 return ret1;
 411         } else
 412                 return 0;
 413 }
 414
 415 static void __exit ipt_cleanup_module(void)
 416 {
 417         tcf_unregister_action(&act_ipt_ops, &ipt_net_ops);
 418         tcf_unregister_action(&act_xt_ops, &xt_net_ops);
 419 }
 420
 421 module_init(ipt_init_module);
 422 module_exit(ipt_cleanup_module);